US9697774B2 - Organic light emitting display having a variable power supply for organic light emitting diode sensing and method of driving the same - Google Patents

Organic light emitting display having a variable power supply for organic light emitting diode sensing and method of driving the same Download PDF

Info

Publication number
US9697774B2
US9697774B2 US14/656,570 US201514656570A US9697774B2 US 9697774 B2 US9697774 B2 US 9697774B2 US 201514656570 A US201514656570 A US 201514656570A US 9697774 B2 US9697774 B2 US 9697774B2
Authority
US
United States
Prior art keywords
organic light
transistor
sensing
voltage
power supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US14/656,570
Other versions
US20160140902A1 (en
Inventor
Jin Wook Yang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Samsung Display Co Ltd
Original Assignee
Samsung Display Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Samsung Display Co Ltd filed Critical Samsung Display Co Ltd
Assigned to SAMSUNG DISPLAY CO., LTD. reassignment SAMSUNG DISPLAY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YANG, JIN WOOK
Publication of US20160140902A1 publication Critical patent/US20160140902A1/en
Application granted granted Critical
Publication of US9697774B2 publication Critical patent/US9697774B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
    • G09G3/3258—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the voltage across the light-emitting element
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3225—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0814—Several active elements per pixel in active matrix panels used for selection purposes, e.g. logical AND for partial update
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0819—Several active elements per pixel in active matrix panels used for counteracting undesired variations, e.g. feedback or autozeroing
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/08—Details of timing specific for flat panels, other than clock recovery
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0223—Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/029—Improving the quality of display appearance by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/043—Preventing or counteracting the effects of ageing
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/043—Preventing or counteracting the effects of ageing
    • G09G2320/045—Compensation of drifts in the characteristics of light emitting or modulating elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/08—Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/2092—Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto

Definitions

  • Embodiments of the present invention relate to an organic light-emitting display and a method of driving the same.
  • flat panel displays have been developed as alternatives to relatively heavy and bulky cathode ray tube (CRT) displays.
  • Examples of flat panel displays include liquid crystal displays (LCD), field emission displays (FEDs), plasma display panels (PDPs), and organic light-emitting displays.
  • organic light-emitting displays display an image using organic light-emitting diodes (OLEDs) that can emit light by electron-hole recombination.
  • OLEDs organic light-emitting diodes
  • Such organic light-emitting displays have features of fast response time and low power consumption.
  • an organic light-emitting display displays a desired image by supplying an electric current corresponding to a gray level to an OLED of each pixel.
  • an image of a desired luminance level cannot be displayed.
  • the degradation of the OLED actually causes the OLED to emit light of a gradually lower luminance level for the same data signal.
  • Embodiments of the present invention provide an organic light-emitting display which can measure highly reliable degradation information by suppressing the generation of a leakage current of a driving transistor.
  • Embodiments of the present invention also provide a method of driving an organic light-emitting display which can measure highly reliable degradation information by suppressing the generation of a leakage current of a driving transistor.
  • an organic light-emitting display including a first transistor including a gate electrode connected to a scan line, a first electrode connected to a data line, and a second electrode connected to a first node, a second transistor including a gate electrode connected to the first node, a first electrode connected to a first power supply voltage, and a second electrode connected to a third node, a third transistor including a gate electrode connected to a sensing control line, a first electrode connected to the data line, and a second electrode connected to the third node and an organic light-emitting device including an anode connected to the third node and a cathode connected to a second power supply voltage, wherein the first power supply voltage is set to a level of a sensing voltage for a period of time during which the sensing voltage is provided to the data line.
  • a same voltage may be applied to the gate electrode, the first electrode and the second electrode of the second transistor.
  • the first transistor and the third transistor may be turned on sequentially.
  • the first transistor and the second transistor may be turned on concurrently.
  • the organic light-emitting display may further include a sensor configured to read out sensing data of the organic light-emitting device corresponding to the sensing voltage.
  • the organic light-emitting display may further include a controller configured to receive the sensing data from the sensor and to generate compensated image data by compensating an image signal received from an external source using the sensing data.
  • the organic light-emitting display may further include a power supply configured to output the first power supply voltage and the second power supply voltage.
  • the controller may be configured to output driving signals for controlling the sensor and the power supply, and the power supply may include a switching device connected to a high-level supply terminal or a sensing-level supply terminal according to the driving signal received from the controller.
  • an organic light-emitting display including a plurality of pixels, each pixel including an organic light-emitting device and a driving transistor including a first electrode connected to the organic light-emitting device, and a second electrode, a sensor configured to read out degradation information of the organic light-emitting device by applying a sensing voltage of a specific level to a gate electrode and the first electrode of the driving transistor and a power supply configured to supply a power supply voltage of a same level as that of the sensing voltage to the second electrode of the driving transistor.
  • Each of the pixels may further include a control transistor configured to supply the sensing voltage to the gate electrode of the driving transistor and a sensing transistor configured to supply the sensing voltage to the first electrode of the driving transistor.
  • control transistor and the sensing transistor may be turned on sequentially.
  • control transistor and the sensing transistor may be turned on concurrently.
  • the sensor may be configured to read out sensing data of the organic light-emitting device corresponding to the sensing voltage.
  • the organic light-emitting display may further include a controller configured to receive the sensing data from the sensor and to generate compensated image data by compensating an image signal received from an external source using the sensing data.
  • the controller may be configured to output driving signals for controlling the sensor and the power supply, and the power supply may include a switching device connected to a high-level supply terminal or a sensing-level supply terminal according to the driving signal received from the controller.
  • a method of driving an organic light-emitting display including a plurality of pixels, each pixel including an organic light-emitting device and a driving transistor including a first electrode connected to the organic light-emitting device and a second electrode, the method including reading out degradation information of the organic light-emitting device by applying a sensing voltage of a specific level to a gate electrode and the first electrode of the driving transistor and generating compensated image data by compensating an image signal received from an external source using the degradation information, wherein a power supply voltage of a same level as that of the sensing voltage is supplied to the second electrode of the driving transistor in the reading out of the degradation information.
  • Each of the pixels may further include a control transistor which supplies the sensing voltage to the gate electrode of the driving transistor and a sensing transistor which supplies the sensing voltage to the first electrode of the driving transistor.
  • control transistor and the sensing transistor may be turned on sequentially.
  • control transistor and the sensing transistor may be turned on concurrently.
  • Compensated image data may be generated by compensating an image signal received from an external source using sensing data corresponding to the degradation information of the organic light-emitting device.
  • FIG. 1 is a block diagram of an organic light-emitting display according to an embodiment of the present invention
  • FIG. 2 is a circuit diagram of an example of a pixel according to an embodiment of the present invention.
  • FIG. 3 is a timing diagram of a sensing mode according to an embodiment of the present invention.
  • FIG. 4 is a diagram schematically illustrating the operation of a pixel in a first period
  • FIG. 5 is a diagram illustrating the operation of the pixel in a second period
  • FIG. 6 is a block diagram of a power supply according to an embodiment of the present invention.
  • FIG. 7 is a block diagram of a controller according to an embodiment of the present invention.
  • FIG. 8 is a timing diagram of a sensing mode of an organic light-emitting display according to another embodiment of the present invention.
  • first, second, and so forth are used to describe diverse constituent elements, such constituent elements are not limited by the terms. The terms are used only to discriminate a constituent element from other constituent elements. Accordingly, in the following description, a first constituent element may be a second constituent element.
  • a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
  • the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the inventive concept refers to “one or more embodiments of the inventive concept.” Also, the term “exemplary” is intended to refer to an example or illustration.
  • the organic light emitting display and/or any other relevant devices or components according to embodiments of the present invention described herein may be implemented utilizing any suitable hardware, firmware (e.g. an application-specific integrated circuit), software, or a suitable combination of software, firmware, and hardware.
  • the various components of the organic light emitting display may be formed on one integrated circuit (IC) chip or on separate IC chips.
  • the various components of the organic light emitting display may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a same substrate as the organic light emitting display.
  • the various components of the organic light emitting display may be a process or thread, running on one or more processors, in one or more computing devices, executing computer program instructions and interacting with other system components for performing the various functionalities described herein.
  • the computer program instructions are stored in a memory which may be implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM).
  • the computer program instructions may also be stored in other non-transitory computer readable media such as, for example, a CD-ROM, flash drive, or the like.
  • FIG. 1 is a block diagram of an organic light-emitting display 10 according to an embodiment of the present invention.
  • FIG. 2 is a circuit diagram of an example of a pixel according to an embodiment of the present invention.
  • the organic light-emitting display 10 includes a display unit (or a display) 110 , a control unit (or a controller) 120 , a data driving unit (or a data driver) 130 , a scan driving unit (or a scan driver) 140 , a sensing control unit (or a sensing controller) 150 , a sensing unit (or a sensor) 160 , and a power supply unit (or a power supply) 170 .
  • the display 110 may be an area where an image is displayed.
  • the display 110 may include a plurality of scan lines, a plurality of data lines crossing the scan lines, and a plurality of pixels PX defined by the scan lines and the data lines. Each of the data lines may cross the scan lines.
  • the pixels PX may be arranged in a matrix.
  • the data lines may extend along a column direction, and the scan lines may extend along a row direction.
  • the display 110 may further include a plurality of power supply lines and a plurality of sensing control lines. Each of the power supply lines and each of the sensing control lines may be connected to a corresponding pixel.
  • the controller 120 may receive a control signal CS and an image signal R, G, and B from an external system.
  • the image signal R, G, and B contains luminance information of the pixels PX.
  • Luminance may have a fixed number of gray levels such as 1024, 256, or 64 gray levels.
  • the control signal CS may include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a clock signal CLK.
  • the controller 120 may generate first through fifth driving signals CONT 1 through CONT 5 and image data DATA according to the image signal R, G, and B and the control signal CS.
  • the controller 120 may generate the image data DATA by dividing the image signal R, G, and B on a frame-by-frame basis according to the vertical synchronization signal Vsync and dividing the image signal R, G, and B on a scan line-by-scan line basis according to the horizontal synchronization signal Hsync.
  • the controller 120 may compensate the image data DATA and transmit the compensated image data DATA 1 to the data driver 130 together with the first driving signal CONT 1 .
  • the generation of the compensated image data DATA 1 will be described in greater detail later.
  • the controller 120 may transmit the second driving signal CONT 2 to the scan driver 140 , the third driving signal CONT 3 to the sensing controller 150 , the fourth driving signal CONT 4 to the sensor 160 , and the fifth driving signal CONT 5 to the power supply 170 .
  • the scan driver 140 may be connected to the scan lines of the display 110 and generate a plurality of scan signals S 1 through Sn according to the second driving signal CONT 2 .
  • the scan driver 140 may sequentially transmit the scan signals S 1 through Sn of a gate-on voltage to the scan lines.
  • the data driver 130 may be connected to the data lines of the display 110 and generate a plurality of data voltages D 1 through Dm by sampling and holding the compensated image data DATA 1 and changing the compensated image data DATA 1 to analog voltages according to the first driving signal CONT 1 .
  • the data driver 130 may transmit the data voltages D 1 through Dm to the data lines, respectively.
  • Each pixel PX of the display 110 may be turned on by a scan signal (S 1 , S 2 , . . . , Sn) of the gate-on voltage and receive a data voltage (D 1 , D 2 , . . . , Dm).
  • the sensor 160 may generate a sensing voltage Vs of a specific level according to the fourth driving signal CONT 4 and supply the sensing voltage Vs to the pixels PX.
  • the sensing voltage Vs may drive an organic light-emitting device EL of each pixel PX at a specific gray level.
  • the sensor 160 may provide the sensing voltage Vs to the data lines. In other words, the sensing voltage Vs may be provided to the pixels PX via the data lines.
  • wiring lines which output the data voltages D 1 through Dm may be disconnected from the data lines.
  • the power supply 170 may provide a first power supply voltage ELVDD and a second power supply voltage ELVSS to the power supply lines connected to the pixels PX.
  • the first power supply voltage ELVDD and the second power supply voltage ELVSS may generate a driving current for each pixel PX.
  • the power supply 170 may determine the level of the first power supply voltage ELVDD according to the fifth driving signal CONT 5 .
  • the level of the first power supply voltage ELVDD may be different in a general operating mode of a display device and in a sensing mode in which degradation information is read out. This will be described in greater detail later.
  • the sensing controller 150 may determine levels of sensing control signals SE 1 through SEn according to the third driving signal CONT 3 and provide the sensing control signals SE 1 through SEn to the sensing control lines connected to the pixels PX. Here, the sensing controller 150 may sequentially provide the sensing control signals SE 1 through SEn to the sensing control lines connected thereto.
  • FIG. 2 is a diagram schematically illustrating the circuit configuration of any one of the pixels PX included in the display 110 .
  • a pixel PXij connected to an i th scan line SLi and a j th data line DLj is illustrated as an example.
  • the circuit configuration of each pixel PX is not limited to the one illustrated in FIG. 2 .
  • the pixel PXij may include a first transistor T 1 , a second transistor T 2 , a third transistor T 3 , a first capacitor C 1 , and an organic light-emitting device EL.
  • the first transistor T 1 may include a gate electrode connected to the scan line SLi, a first electrode connected to the data line DLj, and a second electrode connected to a first node N 1 .
  • the first transistor T 1 may be turned on by a scan signal Si of the gate-on voltage which is transmitted to the scan line SLi.
  • the turned-on first transistor T 1 may deliver a data voltage Dj applied to the data line DLj to the first node N 1 .
  • the first transistor T 1 may be a switching transistor which selectively provides the data voltage Dj to a driving transistor.
  • the first transistor T 1 may be a p-channel field effect transistor. In other words, the first transistor T 1 may be turned on by a scan signal of a low-level voltage and turned off by a scan signal of a high-level voltage.
  • the second transistor T 2 may include a gate electrode connected to the first node N 1 , a first electrode connected to a second node N 2 , and a second electrode connected to a third node N 3 .
  • the second node N 2 may be connected to the first power supply voltage ELVDD.
  • the first capacitor C 1 may be located between the first node N 1 and the second node N 2 .
  • a data voltage provided by the first transistor T 1 may be charged in the first capacitor C 1 , and the charged data voltage may be supplied to the gate electrode of the second transistor T 2 .
  • An anode of the organic light-emitting device EL may be connected to the third node N 3 .
  • the second transistor T 2 may be a driving transistor and control a driving current supplied from the first power supply voltage ELVDD to the organic light-emitting device EL according to the voltage of the first node N 1 .
  • the third transistor T 3 may include a gate electrode connected to a sensing control line SELi, a first electrode connected to the data line DLj, and a second electrode connected to the third node N 3 .
  • the third transistor T 3 may be turned on by a sensing control signal SEi of the gate-on voltage which is transmitted to the sensing control line SELi.
  • the third transistor T 3 may be a sensing transistor.
  • the sensing voltage Vs may be applied to the third node N 3 via the third transistor T 3 .
  • the third transistor T 3 may be turned on in the sensing mode to supply the sensing voltage Vs received through the data line DLj to the third node N 3 .
  • the organic light-emitting device EL may include the anode connected to the third node N 3 , a cathode connected to the second power supply voltage ELVSS, and an organic light-emitting layer.
  • the organic light-emitting layer may emit light of one of primary colors.
  • the primary colors may be three primary colors such as red, green and blue.
  • the spatial or temporal sum of the three primary colors may produce a desired color.
  • the organic light-emitting layer may include low molecular weight organic matter or polymer organic matter corresponding to each color.
  • the organic matter corresponding to each color may emit light according to the amount of electric current flowing through the organic light-emitting layer.
  • a sensing operation according to the current embodiment will now be described in greater detail with reference to FIGS. 3 through 7 .
  • FIG. 3 is a timing diagram of a sensing mode according to an embodiment of the present invention.
  • FIG. 4 is a diagram schematically illustrating the operation of a pixel in a first period t 1 .
  • FIG. 5 is a diagram illustrating the operation of the pixel in a second period t 2 .
  • FIG. 6 is a block diagram of the power supply 170 illustrated in FIG. 1 .
  • FIG. 7 is a block diagram of the controller 120 illustrated in FIG. 1 .
  • the organic light-emitting display 10 can detect degradation information of the organic light-emitting device EL included in each pixel PX.
  • the organic light-emitting display 10 may include a sensing mode for detecting the degradation information of the organic light-emitting device EL.
  • the sensing mode may be activated at specific intervals or by a user's setting during the operation of the organic light-emitting display 10 .
  • the degradation information of the organic light-emitting device EL may be detected in real time based on the sensing voltage Vs applied while the organic light-emitting display 10 is displaying images.
  • the present invention is not limited thereto, and the sensing mode may be activated while the power of the organic light-emitting display 10 is turned off or turned on.
  • the sensing mode may be activated during a standby time when the power is turned on or off.
  • the controller 120 may supply the first through fifth driving signals CONT 1 through CONT 3 to corresponding components, thereby inducing a driving process which will be described later.
  • the sensing mode may include a step of applying the sensing voltage Vs and a step of reading out sensing data SD.
  • FIG. 3 is a timing diagram of the step of applying the sensing voltage Vs.
  • the data driver 130 may be disconnected from the data lines of the display 110 .
  • the data lines may be connected to the sensor 160 , and the sensing voltage Vs may be provided to each data line.
  • the present invention is not limited thereto.
  • the sensing voltage Vs may be applied to the display 110 not through the data lines but through lines other than the data lines.
  • the sensing voltage Vs may be a voltage of a specific level
  • the organic light-emitting device EL may emit light of a luminance level corresponding to an electric current generated by a difference between the sensing voltage Vs and the second power supply voltage ELVSS.
  • the step of applying the sensing voltage Vs may include the first period t 1 and the second period t 2 .
  • the first period t 1 may be a period of time during which the second transistor T 2 (i.e., the driving transistor) is completely shut off, and the second period t 2 may be a period of time during which a voltage difference is created between the terminals of the organic light-emitting device EL by applying the sensing voltage Vs to the third node N 3 .
  • the first period t 1 may be a period of time during which the first transistor T 1 is turned on, and the second period t 2 may be a period of time during which the third transistor T 3 is turned on. In other words, the first transistor T 1 and the third transistor T 3 may be turned on sequentially.
  • the second transistor T 2 (i.e., the driving transistor) may be completely turned off in the first period t 1 . Therefore, the flow of a leakage current generated by the operation of the second transistor T 2 to the organic light-emitting device EL may be prevented or reduced in advance.
  • the same or substantially the same voltage may be applied to the gate electrode and the first electrode of the second transistor T 2 .
  • the sensing voltage Vs of a specific level may be supplied to the gate electrode of the second transistor T 2 .
  • the first transistor T 1 may be turned on by a scan signal and deliver the sensing voltage Vs received through the data line DLj to the gate electrode of the second transistor T 2 .
  • the gate electrode of the second transistor T 2 may be charged with the sensing voltage Vs.
  • the sensing voltage Vs may be a voltage that turns off the second transistor T 2 .
  • the second transistor T 2 i.e., the driving transistor
  • the second transistor T 2 is turned off during the first period t 1 , and thus the generation of the leakage current may be prevented or reduced.
  • a voltage of the same or substantially the same level as that of the sensing voltage Vs may be provided to the second node N 2 to which the first electrode of the first transistor T 1 is connected.
  • the level of the first power supply voltage ELVDD connected to the second node N 2 may be set to the level of the sensing voltage Vs.
  • the power supply 170 may selectively supply a voltage of a high level H and a voltage of the same or substantially the same level as that of the sensing voltage Vs to the first power supply voltage ELVDD.
  • the power supply 170 may switch the level of a voltage supplied to the first power supply voltage ELVDD according to the fifth driving signal CONT 5 .
  • the power supply 170 may include a switching device that is controlled according to the fifth driving signal CONT 5 .
  • the switching device may be connected to a high-level voltage supply terminal or a sensing voltage-level voltage supply terminal according to the fifth driving signal CONT 5 .
  • the first power supply voltage ELVDD may be at the high level H until the sensing mode is activated. In other words, the first power supply voltage ELVDD may maintain the high level H such that a voltage difference is created between the terminals of the second transistor T 2 (i.e., the driving transistor). However, when the sensing mode is activated, the level of the first power supply voltage ELVDD may be set to the level of the sensing voltage Vs. Since the sensing voltage Vs is supplied to the third node N 3 in the second period t 2 , it may be applied to both the first and second electrodes of the second transistor T 2 (i.e., the driving transistor). In other words, a voltage difference between the first and second electrodes of the second transistor T 2 may be 0 V. Accordingly, the generation of an electric current by the second transistor T 2 may be completely or substantially prevented.
  • the sensing voltage Vs may be applied to the third node N 3 in the second period t 2 .
  • the third transistor T 3 may be turned on by a sensing control signal, and the sensing voltage Vs supplied through the data line DLj may be provided to the third node N 3 through the third transistor T 3 .
  • the third node N 3 may be connected to the second electrode of the second transistor T 2 (i.e., the driving transistor) and the anode of the organic light-emitting device EL.
  • an electric potential of the same or substantially the same level as that of the sensing voltage Vs may be formed.
  • the third node N 3 may have the same or substantially the same voltage as the second node N 2 . Accordingly, a voltage difference between the first and second electrodes of the second transistor T 2 (i.e., the driving transistor) may be substantially 0 V, and the generation of the leakage current by the second transistor T 2 may be completely or substantially prevented as described above. Since the first electrode of the organic light-emitting device EL is connected to the third node N 3 and the second electrode of the organic light-emitting device EL is connected to the second power supply voltage ELVSS, a specific voltage difference may be created between both terminals of the organic light-emitting device EL.
  • an electric current corresponding to this voltage difference may flow through the organic light-emitting device EL, causing the organic light-emitting device EL to emit light at a specific luminance level.
  • the organic light-emitting device EL emits light at a low luminance level for a very short period of time. Therefore, even if the sensing mode is activated during the normal operation of the organic light-emitting display 10 , a luminance change due to the sensing mode is not substantially visible to a user.
  • the sensor 160 may read out the sensing data SD.
  • the sensing data SD may be detected using one or more of various suitable known methods.
  • the sensing data SD may be read out by measuring the luminance of the organic light-emitting device EL.
  • the present invention is not limited thereto, and the sensing data SD may also be read out by measuring a current or voltage flowing through the organic light-emitting device EL.
  • the sensor 160 may convert the read-out sensing data SD into a digital value.
  • the digital value generated by each pixel PX may be mapped to a memory unit (or memory) and provided to the controller 120 as the sensing data SD.
  • the controller 120 may generate the compensated image data DATA 1 by compensating the image data DATA using the received sensing data SD.
  • the controller 120 may include a signal processor 121 which generates the first through fifth driving signals CONT 1 through CONT 5 , an image processor 122 which generates the image data DATA by processing the image signal R, G, and B, and an image compensator 123 which compensates the image data DATA.
  • the image compensator 123 may generate the compensated image data DATA 1 using the sensing data SD provided by the sensor 160 and the image data DATA provided by the image processor 122 .
  • the compensated image data DATA 1 may be data obtained by compensating for the degradation of the organic light-emitting device EL of each pixel PX.
  • the image compensator 123 may generate the compensated image data DATA 1 by correcting the image data DATA such that a voltage increased by an amount corresponding to a luminance reduction caused by the degradation of the organic light-emitting device EL may be applied to a degraded pixel.
  • the organic light-emitting display 10 may prevent or substantially prevent the second transistor T 2 (i.e., the driving transistor) from generating the leakage current by completely shutting off the second transistor T 2 . Accordingly, the degradation information of the organic light-emitting device EL may be read out more accurately based on the sensing voltage Vs, making more accurate data compensation possible.
  • the second transistor T 2 i.e., the driving transistor
  • FIG. 8 is a timing diagram of a sensing mode of an organic light-emitting display according to another embodiment of the present invention.
  • the organic light-emitting display according to the current embodiment is different from the organic light-emitting display 10 of FIGS. 1 through 7 in that a scan signal and a sensing control signal are transmitted concurrently (e.g., simultaneously).
  • a scan signal and a sensing control signal are transmitted concurrently (e.g., simultaneously).
  • a description of components substantially identical to those of the previous embodiment may be omitted, and the current embodiment will hereinafter be described, focusing mainly on differences with the previous embodiment.
  • the scan signal and the sensing control signal may be provided at the same or substantially the same time.
  • a first transistor T 1 and a third transistor T 3 may be turned on concurrently (e.g., simultaneously). Since a sensing voltage Vs is supplied through the same data line, a gate electrode of a second transistor T 2 may be diode-connected to a second electrode of the second transistor T 2 .
  • the level of a first power supply voltage ELVDD may be set to the level of the sensing voltage Vs at the same or substantially the same time as when the first transistor T 1 and the third transistor T 3 are turned on.
  • voltage levels of the gate electrode, a first electrode and the second electrode of the second transistor T 2 may all be set to the level of the sensing voltage Vs. Accordingly, the generation of an electric current by the second transistor T 2 may be completely or substantially prevented, thus preventing or reducing a leakage current from flowing to an organic light-emitting device EL.
  • the organic light-emitting display according to the current embodiment may turn off the driving transistor by concurrently (e.g., simultaneously) applying the same or substantially the same voltage to the gate electrode, the first electrode and the second electrode of the driving transistor. Therefore, the time required to apply the sensing voltage Vs may be reduced.
  • the method of driving the organic light-emitting display according to the current embodiment of the present invention includes applying a sensing voltage (operation S 110 ) and generating compensated image data (operation S 120 ).
  • the organic light-emitting display includes a plurality of pixels PX, each including an organic light-emitting device EL and a second transistor T 2 (i.e., a driving transistor) having a first electrode connected to the organic light-emitting device EL.
  • the organic light-emitting display may be the organic light-emitting display 10 of FIGS. 1 through 7 , and thus a detailed description thereof will be omitted.
  • FIGS. 1 through 7 will be referred to for the description of the current embodiment.
  • the duration of applying of the sensing voltage may include a first period t 1 and a second period t 2 .
  • the first period t 1 may be a period of time during which the second transistor T 2 (i.e., the driving transistor) is completely shut off, and the second period t 2 may be a period of time during which a voltage difference is created between both terminals of the organic light-emitting device EL by applying a sensing voltage Vs to a third node N 3 .
  • the first period t 1 may be a period of time during which a first transistor T 1 is turned on, and the second period t 2 may be a period of time during which a third transistor T 3 is turned on. In other words, the first transistor T 1 and the third transistor T 3 may be turned on sequentially.
  • the second transistor T 2 (i.e., the driving transistor) may be completely turned off. Specifically, in the first period t 1 , the same or substantially the same voltage may be applied to a gate electrode and the first electrode of the second transistor T 2 .
  • the sensing voltage Vs of a specific level may be supplied to the gate electrode of the second transistor T 2 .
  • the first transistor T 1 may be turned on by a scan signal and deliver the sensing voltage Vs received through a data line DLj to the gate electrode of the second transistor T 2 .
  • the gate electrode of the second transistor T 2 may be charged with the sensing voltage Vs.
  • the sensing voltage Vs may be a voltage that turns off the second transistor T 2 .
  • the second transistor T 2 (i.e., the driving transistor) may be turned off by the sensing voltage Vs.
  • a voltage of the same or substantially the same level as that of the sensing voltage Vs may be provided to a second node N 2 to which a first electrode of the first transistor T 1 is connected.
  • the level of a first power supply voltage ELVDD connected to the second node N 2 may be set to the level of the sensing voltage Vs.
  • the first power supply voltage ELVDD may be at a high level H until a sensing mode is activated.
  • the first power supply voltage ELVDD may maintain the high level H such that a voltage difference is created between the terminals of the second transistor T 2 (i.e., the driving transistor).
  • the level of the first power supply voltage ELVDD may be set to the level of the sensing voltage Vs. Since the sensing voltage Vs is supplied to the third node N 3 in the second period t 2 , it may be applied to both the first and second electrodes of the second transistor T 2 (i.e., the driving transistor). In other words, a voltage difference between the first and second electrodes of the second transistor T 2 may be 0 V. Accordingly, the generation of an electric current by the second transistor T 2 may be completely or substantially prevented.
  • the sensing voltage Vs may be applied to the third node N 3 .
  • the third transistor T 3 may be turned on by a sensing control signal, and the sensing voltage Vs supplied through the data line DLj may be provided to the third node N 3 through the third transistor T 3 .
  • the third node N 3 may be charged with the sensing voltage Vs, and a voltage difference between the first and second electrodes of the second transistor T 2 (i.e., the driving transistor) may be substantially 0 V.
  • the second transistor T 2 may be completely turned off.
  • a specific voltage difference may be created between both terminals of the organic light-emitting device EL. Accordingly, an electric current corresponding to this voltage difference may flow through the organic light-emitting device EL, causing the organic light-emitting device EL to emit light at a specific luminance level.
  • compensated image data is generated (operation S 120 ).
  • a sensor 160 may read out degradation information based on the sensing voltage Vs.
  • sensing data SD may be detected using various suitable known methods.
  • the sensing data SD may be read out by measuring the luminance of the organic light-emitting device EL.
  • the present invention is not limited thereto, and the sensing data SD may also be read out by measuring a current or voltage flowing through the organic light-emitting device EL.
  • the sensor 160 may convert the read-out sensing data SD into a digital value.
  • the digital value generated by each pixel PX may be mapped to a memory unit (or memory) and provided to a controller 120 as the sensing data SD.
  • the controller 120 may generate compensated image data DATA 1 by compensating image data DATA using the received sensing data SD.
  • an image compensator 123 may generate the compensated image data DATA 1 by correcting the image data DATA such that a voltage increased by an amount corresponding to a luminance reduction caused by the degradation of the organic light-emitting device EL may be applied to a degraded pixel.
  • the method of driving the organic light-emitting display according to the current embodiment may prevent or reduce the generation of a leakage current by completely shutting off the second transistor T 2 (i.e., the driving transistor). Accordingly, the degradation information of the organic light-emitting device EL may be read out more accurately based on the sensing voltage Vs, making more accurate data compensation possible.
  • the first transistor T 1 and the third transistor T 3 may be turned on concurrently (e.g., simultaneously).
  • a scan signal and a sensing control signal may be provided at the same or substantially the same time.
  • Voltage levels of the gate electrode, the first electrode and the second electrode of the second transistor T 2 i.e., a driving transistor
  • the driving transistor may be turned off by concurrently (e.g., simultaneously applying the same or substantially the same voltage to the gate electrode, the first electrode and the second electrode of the driving transistor. Therefore, the time required to apply the sensing voltage Vs may be reduced.
  • Embodiments of the present invention provide at least one of the following aspects.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of El Displays (AREA)
  • Electroluminescent Light Sources (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

An organic light-emitting display comprises a first transistor comprising a gate electrode connected to a scan line, a first electrode connected to a data line, and a second electrode connected to a first node, a second transistor comprising a gate electrode connected to the first node, a first electrode connected to a first power supply voltage, and a second electrode connected to a third node, a third transistor comprising a gate electrode connected to a sensing control line, a first electrode connected to the data line, and a second electrode connected to the third node and an organic light-emitting device comprising an anode connected to the third node and a cathode connected to a second power supply voltage, wherein the first power supply voltage is set to a level of a sensing voltage for a period of time during which the sensing voltage is provided to the data line.

Description

CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of Korean Patent Application No. 10-2014-0161646 filed on Nov. 19, 2014 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.
BACKGROUND
1. Field
Embodiments of the present invention relate to an organic light-emitting display and a method of driving the same.
2. Description of the Related Art
Recently, various flat panel displays have been developed as alternatives to relatively heavy and bulky cathode ray tube (CRT) displays. Examples of flat panel displays include liquid crystal displays (LCD), field emission displays (FEDs), plasma display panels (PDPs), and organic light-emitting displays.
Among the flat panel displays, organic light-emitting displays display an image using organic light-emitting diodes (OLEDs) that can emit light by electron-hole recombination. Such organic light-emitting displays have features of fast response time and low power consumption. Generally, an organic light-emitting display displays a desired image by supplying an electric current corresponding to a gray level to an OLED of each pixel. However, since the OLED is degraded over time, an image of a desired luminance level cannot be displayed. The degradation of the OLED actually causes the OLED to emit light of a gradually lower luminance level for the same data signal.
To overcome this problem, a method of compensating for degradation of an OLED by extracting degradation information of the OLED from a pixel and changing data using the extracted degradation information has been suggested. In this degradation compensation method, however, a leakage current of a driving transistor may be included in the degradation information when the degradation information is extracted. Therefore, the reliability of the degradation information may be reduced.
SUMMARY
Embodiments of the present invention provide an organic light-emitting display which can measure highly reliable degradation information by suppressing the generation of a leakage current of a driving transistor.
Embodiments of the present invention also provide a method of driving an organic light-emitting display which can measure highly reliable degradation information by suppressing the generation of a leakage current of a driving transistor.
However, embodiments of the present invention are not restricted to the ones set forth herein. The above and other aspects of embodiments of the present invention will become more apparent to one of ordinary skill in the art to which the present invention pertains by referencing the detailed description of embodiments of the present invention given below.
According to an embodiment of the present invention, there is provided an organic light-emitting display including a first transistor including a gate electrode connected to a scan line, a first electrode connected to a data line, and a second electrode connected to a first node, a second transistor including a gate electrode connected to the first node, a first electrode connected to a first power supply voltage, and a second electrode connected to a third node, a third transistor including a gate electrode connected to a sensing control line, a first electrode connected to the data line, and a second electrode connected to the third node and an organic light-emitting device including an anode connected to the third node and a cathode connected to a second power supply voltage, wherein the first power supply voltage is set to a level of a sensing voltage for a period of time during which the sensing voltage is provided to the data line.
A same voltage may be applied to the gate electrode, the first electrode and the second electrode of the second transistor.
The first transistor and the third transistor may be turned on sequentially.
The first transistor and the second transistor may be turned on concurrently.
The organic light-emitting display may further include a sensor configured to read out sensing data of the organic light-emitting device corresponding to the sensing voltage.
The organic light-emitting display may further include a controller configured to receive the sensing data from the sensor and to generate compensated image data by compensating an image signal received from an external source using the sensing data.
The organic light-emitting display may further include a power supply configured to output the first power supply voltage and the second power supply voltage.
The controller may be configured to output driving signals for controlling the sensor and the power supply, and the power supply may include a switching device connected to a high-level supply terminal or a sensing-level supply terminal according to the driving signal received from the controller.
According to another embodiment of the present invention, there is provided an organic light-emitting display including a plurality of pixels, each pixel including an organic light-emitting device and a driving transistor including a first electrode connected to the organic light-emitting device, and a second electrode, a sensor configured to read out degradation information of the organic light-emitting device by applying a sensing voltage of a specific level to a gate electrode and the first electrode of the driving transistor and a power supply configured to supply a power supply voltage of a same level as that of the sensing voltage to the second electrode of the driving transistor.
Each of the pixels may further include a control transistor configured to supply the sensing voltage to the gate electrode of the driving transistor and a sensing transistor configured to supply the sensing voltage to the first electrode of the driving transistor.
The control transistor and the sensing transistor may be turned on sequentially.
The control transistor and the sensing transistor may be turned on concurrently.
The sensor may be configured to read out sensing data of the organic light-emitting device corresponding to the sensing voltage.
The organic light-emitting display may further include a controller configured to receive the sensing data from the sensor and to generate compensated image data by compensating an image signal received from an external source using the sensing data.
The controller may be configured to output driving signals for controlling the sensor and the power supply, and the power supply may include a switching device connected to a high-level supply terminal or a sensing-level supply terminal according to the driving signal received from the controller.
According to another embodiment of the present invention, there is provided a method of driving an organic light-emitting display including a plurality of pixels, each pixel including an organic light-emitting device and a driving transistor including a first electrode connected to the organic light-emitting device and a second electrode, the method including reading out degradation information of the organic light-emitting device by applying a sensing voltage of a specific level to a gate electrode and the first electrode of the driving transistor and generating compensated image data by compensating an image signal received from an external source using the degradation information, wherein a power supply voltage of a same level as that of the sensing voltage is supplied to the second electrode of the driving transistor in the reading out of the degradation information.
Each of the pixels may further include a control transistor which supplies the sensing voltage to the gate electrode of the driving transistor and a sensing transistor which supplies the sensing voltage to the first electrode of the driving transistor.
The control transistor and the sensing transistor may be turned on sequentially.
The control transistor and the sensing transistor may be turned on concurrently.
Compensated image data may be generated by compensating an image signal received from an external source using sensing data corresponding to the degradation information of the organic light-emitting device.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects and features of embodiments of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
FIG. 1 is a block diagram of an organic light-emitting display according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of an example of a pixel according to an embodiment of the present invention;
FIG. 3 is a timing diagram of a sensing mode according to an embodiment of the present invention;
FIG. 4 is a diagram schematically illustrating the operation of a pixel in a first period;
FIG. 5 is a diagram illustrating the operation of the pixel in a second period;
FIG. 6 is a block diagram of a power supply according to an embodiment of the present invention;
FIG. 7 is a block diagram of a controller according to an embodiment of the present invention; and
FIG. 8 is a timing diagram of a sensing mode of an organic light-emitting display according to another embodiment of the present invention.
 DETAILED DESCRIPTION
The aspects and features of embodiments of the present invention and methods for achieving the aspects and features will be apparent by referring to the embodiments to be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed hereinafter, but can be implemented in diverse forms. The matters defined in the description, such as the detailed construction and elements, are specific details provided to assist those of ordinary skill in the art in a comprehensive understanding of the present invention, and the present invention is only defined within the scope of the appended claims and their equivalents.
The term “on” that is used to designate that an element is on another element or located on a different layer or a layer includes both a case where an element is located directly on another element or a layer and a case where an element is located on another element via another layer or still another element. Throughout the description of embodiments of the present invention, the same drawing reference numerals are used for the same elements across various figures.
Although the terms “first, second, and so forth” are used to describe diverse constituent elements, such constituent elements are not limited by the terms. The terms are used only to discriminate a constituent element from other constituent elements. Accordingly, in the following description, a first constituent element may be a second constituent element. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” “including,” and “include,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the inventive concept refers to “one or more embodiments of the inventive concept.” Also, the term “exemplary” is intended to refer to an example or illustration.
It will be understood that when an element or layer is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another element or layer, it can be directly on, connected to, coupled to, or adjacent to the other element or layer, or one or more intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on,” “directly connected to”, “directly coupled to”, or “immediately adjacent to” another element or layer, there are no intervening elements or layers present.
As used herein, the term “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art.
As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.
The organic light emitting display and/or any other relevant devices or components according to embodiments of the present invention described herein may be implemented utilizing any suitable hardware, firmware (e.g. an application-specific integrated circuit), software, or a suitable combination of software, firmware, and hardware. For example, the various components of the organic light emitting display may be formed on one integrated circuit (IC) chip or on separate IC chips. Further, the various components of the organic light emitting display may be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a same substrate as the organic light emitting display. Further, the various components of the organic light emitting display may be a process or thread, running on one or more processors, in one or more computing devices, executing computer program instructions and interacting with other system components for performing the various functionalities described herein. The computer program instructions are stored in a memory which may be implemented in a computing device using a standard memory device, such as, for example, a random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer readable media such as, for example, a CD-ROM, flash drive, or the like. Also, a person of skill in the art should recognize that the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a particular computing device may be distributed across one or more other computing devices without departing from the scope of the exemplary embodiments of the present invention.
Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.
FIG. 1 is a block diagram of an organic light-emitting display 10 according to an embodiment of the present invention. FIG. 2 is a circuit diagram of an example of a pixel according to an embodiment of the present invention.
Referring to FIGS. 1 and 2, the organic light-emitting display 10 includes a display unit (or a display) 110, a control unit (or a controller) 120, a data driving unit (or a data driver) 130, a scan driving unit (or a scan driver) 140, a sensing control unit (or a sensing controller) 150, a sensing unit (or a sensor) 160, and a power supply unit (or a power supply) 170.
The display 110 may be an area where an image is displayed. The display 110 may include a plurality of scan lines, a plurality of data lines crossing the scan lines, and a plurality of pixels PX defined by the scan lines and the data lines. Each of the data lines may cross the scan lines. The pixels PX may be arranged in a matrix. The data lines may extend along a column direction, and the scan lines may extend along a row direction. The display 110 may further include a plurality of power supply lines and a plurality of sensing control lines. Each of the power supply lines and each of the sensing control lines may be connected to a corresponding pixel.
The controller 120 may receive a control signal CS and an image signal R, G, and B from an external system. The image signal R, G, and B contains luminance information of the pixels PX. Luminance may have a fixed number of gray levels such as 1024, 256, or 64 gray levels. The control signal CS may include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a clock signal CLK. The controller 120 may generate first through fifth driving signals CONT1 through CONT5 and image data DATA according to the image signal R, G, and B and the control signal CS. The controller 120 may generate the image data DATA by dividing the image signal R, G, and B on a frame-by-frame basis according to the vertical synchronization signal Vsync and dividing the image signal R, G, and B on a scan line-by-scan line basis according to the horizontal synchronization signal Hsync. The controller 120 may compensate the image data DATA and transmit the compensated image data DATA1 to the data driver 130 together with the first driving signal CONT1. The generation of the compensated image data DATA1 will be described in greater detail later. The controller 120 may transmit the second driving signal CONT2 to the scan driver 140, the third driving signal CONT3 to the sensing controller 150, the fourth driving signal CONT4 to the sensor 160, and the fifth driving signal CONT5 to the power supply 170.
The scan driver 140 may be connected to the scan lines of the display 110 and generate a plurality of scan signals S1 through Sn according to the second driving signal CONT2. The scan driver 140 may sequentially transmit the scan signals S1 through Sn of a gate-on voltage to the scan lines.
The data driver 130 may be connected to the data lines of the display 110 and generate a plurality of data voltages D1 through Dm by sampling and holding the compensated image data DATA1 and changing the compensated image data DATA1 to analog voltages according to the first driving signal CONT1. The data driver 130 may transmit the data voltages D1 through Dm to the data lines, respectively. Each pixel PX of the display 110 may be turned on by a scan signal (S1, S2, . . . , Sn) of the gate-on voltage and receive a data voltage (D1, D2, . . . , Dm).
The sensor 160 may generate a sensing voltage Vs of a specific level according to the fourth driving signal CONT4 and supply the sensing voltage Vs to the pixels PX. The sensing voltage Vs may drive an organic light-emitting device EL of each pixel PX at a specific gray level. The sensor 160 may provide the sensing voltage Vs to the data lines. In other words, the sensing voltage Vs may be provided to the pixels PX via the data lines. When the sensor 160 provides the sensing voltage Vs, wiring lines which output the data voltages D1 through Dm may be disconnected from the data lines.
The power supply 170 may provide a first power supply voltage ELVDD and a second power supply voltage ELVSS to the power supply lines connected to the pixels PX. The first power supply voltage ELVDD and the second power supply voltage ELVSS may generate a driving current for each pixel PX. The power supply 170 may determine the level of the first power supply voltage ELVDD according to the fifth driving signal CONT5. In other words, the level of the first power supply voltage ELVDD may be different in a general operating mode of a display device and in a sensing mode in which degradation information is read out. This will be described in greater detail later.
The sensing controller 150 may determine levels of sensing control signals SE1 through SEn according to the third driving signal CONT3 and provide the sensing control signals SE1 through SEn to the sensing control lines connected to the pixels PX. Here, the sensing controller 150 may sequentially provide the sensing control signals SE1 through SEn to the sensing control lines connected thereto.
FIG. 2 is a diagram schematically illustrating the circuit configuration of any one of the pixels PX included in the display 110. In other words, a pixel PXij connected to an ith scan line SLi and a jth data line DLj is illustrated as an example. However, the circuit configuration of each pixel PX is not limited to the one illustrated in FIG. 2.
Referring to FIG. 2, the pixel PXij may include a first transistor T1, a second transistor T2, a third transistor T3, a first capacitor C1, and an organic light-emitting device EL.
The first transistor T1 may include a gate electrode connected to the scan line SLi, a first electrode connected to the data line DLj, and a second electrode connected to a first node N1. The first transistor T1 may be turned on by a scan signal Si of the gate-on voltage which is transmitted to the scan line SLi. The turned-on first transistor T1 may deliver a data voltage Dj applied to the data line DLj to the first node N1. The first transistor T1 may be a switching transistor which selectively provides the data voltage Dj to a driving transistor. Here, the first transistor T1 may be a p-channel field effect transistor. In other words, the first transistor T1 may be turned on by a scan signal of a low-level voltage and turned off by a scan signal of a high-level voltage.
The second transistor T2 may include a gate electrode connected to the first node N1, a first electrode connected to a second node N2, and a second electrode connected to a third node N3. Here, the second node N2 may be connected to the first power supply voltage ELVDD. The first capacitor C1 may be located between the first node N1 and the second node N2. A data voltage provided by the first transistor T1 may be charged in the first capacitor C1, and the charged data voltage may be supplied to the gate electrode of the second transistor T2. An anode of the organic light-emitting device EL may be connected to the third node N3. The second transistor T2 may be a driving transistor and control a driving current supplied from the first power supply voltage ELVDD to the organic light-emitting device EL according to the voltage of the first node N1.
The third transistor T3 may include a gate electrode connected to a sensing control line SELi, a first electrode connected to the data line DLj, and a second electrode connected to the third node N3. The third transistor T3 may be turned on by a sensing control signal SEi of the gate-on voltage which is transmitted to the sensing control line SELi. Here, the third transistor T3 may be a sensing transistor. In other words, the sensing voltage Vs may be applied to the third node N3 via the third transistor T3. In other words, the third transistor T3 may be turned on in the sensing mode to supply the sensing voltage Vs received through the data line DLj to the third node N3.
The organic light-emitting device EL may include the anode connected to the third node N3, a cathode connected to the second power supply voltage ELVSS, and an organic light-emitting layer. The organic light-emitting layer may emit light of one of primary colors. The primary colors may be three primary colors such as red, green and blue. The spatial or temporal sum of the three primary colors may produce a desired color. The organic light-emitting layer may include low molecular weight organic matter or polymer organic matter corresponding to each color. The organic matter corresponding to each color may emit light according to the amount of electric current flowing through the organic light-emitting layer. A sensing operation according to the current embodiment will now be described in greater detail with reference to FIGS. 3 through 7.
FIG. 3 is a timing diagram of a sensing mode according to an embodiment of the present invention. FIG. 4 is a diagram schematically illustrating the operation of a pixel in a first period t1. FIG. 5 is a diagram illustrating the operation of the pixel in a second period t2. FIG. 6 is a block diagram of the power supply 170 illustrated in FIG. 1. FIG. 7 is a block diagram of the controller 120 illustrated in FIG. 1.
Referring to FIGS. 3 through 7, the organic light-emitting display 10 according to the current embodiment can detect degradation information of the organic light-emitting device EL included in each pixel PX. In other words, the organic light-emitting display 10 may include a sensing mode for detecting the degradation information of the organic light-emitting device EL. The sensing mode may be activated at specific intervals or by a user's setting during the operation of the organic light-emitting display 10. In other words, the degradation information of the organic light-emitting device EL may be detected in real time based on the sensing voltage Vs applied while the organic light-emitting display 10 is displaying images. However, the present invention is not limited thereto, and the sensing mode may be activated while the power of the organic light-emitting display 10 is turned off or turned on. In other words, the sensing mode may be activated during a standby time when the power is turned on or off. After the sensing mode is activated, the controller 120 may supply the first through fifth driving signals CONT1 through CONT3 to corresponding components, thereby inducing a driving process which will be described later.
The sensing mode may include a step of applying the sensing voltage Vs and a step of reading out sensing data SD. FIG. 3 is a timing diagram of the step of applying the sensing voltage Vs. In the sensing mode, the data driver 130 may be disconnected from the data lines of the display 110. In other words, the data lines may be connected to the sensor 160, and the sensing voltage Vs may be provided to each data line. However, the present invention is not limited thereto. In some embodiments, the sensing voltage Vs may be applied to the display 110 not through the data lines but through lines other than the data lines. Here, the sensing voltage Vs may be a voltage of a specific level, and the organic light-emitting device EL may emit light of a luminance level corresponding to an electric current generated by a difference between the sensing voltage Vs and the second power supply voltage ELVSS.
The step of applying the sensing voltage Vs according to the current embodiment may include the first period t1 and the second period t2. The first period t1 may be a period of time during which the second transistor T2 (i.e., the driving transistor) is completely shut off, and the second period t2 may be a period of time during which a voltage difference is created between the terminals of the organic light-emitting device EL by applying the sensing voltage Vs to the third node N3. The first period t1 may be a period of time during which the first transistor T1 is turned on, and the second period t2 may be a period of time during which the third transistor T3 is turned on. In other words, the first transistor T1 and the third transistor T3 may be turned on sequentially.
More specifically, the second transistor T2 (i.e., the driving transistor) may be completely turned off in the first period t1. Therefore, the flow of a leakage current generated by the operation of the second transistor T2 to the organic light-emitting device EL may be prevented or reduced in advance. Specifically, in the first period t1, the same or substantially the same voltage may be applied to the gate electrode and the first electrode of the second transistor T2. The sensing voltage Vs of a specific level may be supplied to the gate electrode of the second transistor T2. In other words, in the first period t1, the first transistor T1 may be turned on by a scan signal and deliver the sensing voltage Vs received through the data line DLj to the gate electrode of the second transistor T2. The gate electrode of the second transistor T2 may be charged with the sensing voltage Vs. The sensing voltage Vs may be a voltage that turns off the second transistor T2. In other words, the second transistor T2 (i.e., the driving transistor) may be turned off by the sensing voltage Vs. The second transistor T2 is turned off during the first period t1, and thus the generation of the leakage current may be prevented or reduced. Referring to FIG. 4, a voltage of the same or substantially the same level as that of the sensing voltage Vs may be provided to the second node N2 to which the first electrode of the first transistor T1 is connected. In other words, the level of the first power supply voltage ELVDD connected to the second node N2 may be set to the level of the sensing voltage Vs.
Referring to FIG. 6, the power supply 170 may selectively supply a voltage of a high level H and a voltage of the same or substantially the same level as that of the sensing voltage Vs to the first power supply voltage ELVDD. The power supply 170 may switch the level of a voltage supplied to the first power supply voltage ELVDD according to the fifth driving signal CONT5. The power supply 170 may include a switching device that is controlled according to the fifth driving signal CONT5. The switching device may be connected to a high-level voltage supply terminal or a sensing voltage-level voltage supply terminal according to the fifth driving signal CONT5.
The first power supply voltage ELVDD may be at the high level H until the sensing mode is activated. In other words, the first power supply voltage ELVDD may maintain the high level H such that a voltage difference is created between the terminals of the second transistor T2 (i.e., the driving transistor). However, when the sensing mode is activated, the level of the first power supply voltage ELVDD may be set to the level of the sensing voltage Vs. Since the sensing voltage Vs is supplied to the third node N3 in the second period t2, it may be applied to both the first and second electrodes of the second transistor T2 (i.e., the driving transistor). In other words, a voltage difference between the first and second electrodes of the second transistor T2 may be 0 V. Accordingly, the generation of an electric current by the second transistor T2 may be completely or substantially prevented.
Referring to FIG. 5, the sensing voltage Vs may be applied to the third node N3 in the second period t2. In the second period t2, the third transistor T3 may be turned on by a sensing control signal, and the sensing voltage Vs supplied through the data line DLj may be provided to the third node N3 through the third transistor T3. The third node N3 may be connected to the second electrode of the second transistor T2 (i.e., the driving transistor) and the anode of the organic light-emitting device EL. In the third node N3, an electric potential of the same or substantially the same level as that of the sensing voltage Vs may be formed. Thus, the third node N3 may have the same or substantially the same voltage as the second node N2. Accordingly, a voltage difference between the first and second electrodes of the second transistor T2 (i.e., the driving transistor) may be substantially 0 V, and the generation of the leakage current by the second transistor T2 may be completely or substantially prevented as described above. Since the first electrode of the organic light-emitting device EL is connected to the third node N3 and the second electrode of the organic light-emitting device EL is connected to the second power supply voltage ELVSS, a specific voltage difference may be created between both terminals of the organic light-emitting device EL. Accordingly, an electric current corresponding to this voltage difference may flow through the organic light-emitting device EL, causing the organic light-emitting device EL to emit light at a specific luminance level. In the sensing mode, the organic light-emitting device EL emits light at a low luminance level for a very short period of time. Therefore, even if the sensing mode is activated during the normal operation of the organic light-emitting display 10, a luminance change due to the sensing mode is not substantially visible to a user.
The sensor 160 may read out the sensing data SD. The sensing data SD may be detected using one or more of various suitable known methods. For example, the sensing data SD may be read out by measuring the luminance of the organic light-emitting device EL. However, the present invention is not limited thereto, and the sensing data SD may also be read out by measuring a current or voltage flowing through the organic light-emitting device EL. The sensor 160 may convert the read-out sensing data SD into a digital value. The digital value generated by each pixel PX may be mapped to a memory unit (or memory) and provided to the controller 120 as the sensing data SD.
Referring to FIG. 7, the controller 120 may generate the compensated image data DATA1 by compensating the image data DATA using the received sensing data SD. The controller 120 may include a signal processor 121 which generates the first through fifth driving signals CONT1 through CONT5, an image processor 122 which generates the image data DATA by processing the image signal R, G, and B, and an image compensator 123 which compensates the image data DATA. The image compensator 123 may generate the compensated image data DATA1 using the sensing data SD provided by the sensor 160 and the image data DATA provided by the image processor 122. The compensated image data DATA1 may be data obtained by compensating for the degradation of the organic light-emitting device EL of each pixel PX. The image compensator 123 may generate the compensated image data DATA1 by correcting the image data DATA such that a voltage increased by an amount corresponding to a luminance reduction caused by the degradation of the organic light-emitting device EL may be applied to a degraded pixel.
The organic light-emitting display 10 according to the current embodiment may prevent or substantially prevent the second transistor T2 (i.e., the driving transistor) from generating the leakage current by completely shutting off the second transistor T2. Accordingly, the degradation information of the organic light-emitting device EL may be read out more accurately based on the sensing voltage Vs, making more accurate data compensation possible.
An organic light-emitting display according to another embodiment of the present invention will now be described.
FIG. 8 is a timing diagram of a sensing mode of an organic light-emitting display according to another embodiment of the present invention. The organic light-emitting display according to the current embodiment is different from the organic light-emitting display 10 of FIGS. 1 through 7 in that a scan signal and a sensing control signal are transmitted concurrently (e.g., simultaneously). For simplicity, a description of components substantially identical to those of the previous embodiment may be omitted, and the current embodiment will hereinafter be described, focusing mainly on differences with the previous embodiment.
In the organic light-emitting display according to the current embodiment, the scan signal and the sensing control signal may be provided at the same or substantially the same time. In other words, a first transistor T1 and a third transistor T3 may be turned on concurrently (e.g., simultaneously). Since a sensing voltage Vs is supplied through the same data line, a gate electrode of a second transistor T2 may be diode-connected to a second electrode of the second transistor T2. However, the level of a first power supply voltage ELVDD may be set to the level of the sensing voltage Vs at the same or substantially the same time as when the first transistor T1 and the third transistor T3 are turned on. In other words, voltage levels of the gate electrode, a first electrode and the second electrode of the second transistor T2 (i.e., a driving transistor) may all be set to the level of the sensing voltage Vs. Accordingly, the generation of an electric current by the second transistor T2 may be completely or substantially prevented, thus preventing or reducing a leakage current from flowing to an organic light-emitting device EL. The organic light-emitting display according to the current embodiment may turn off the driving transistor by concurrently (e.g., simultaneously) applying the same or substantially the same voltage to the gate electrode, the first electrode and the second electrode of the driving transistor. Therefore, the time required to apply the sensing voltage Vs may be reduced.
A method of driving an organic light-emitting display according to an embodiment of the present invention will now be described.
The method of driving the organic light-emitting display according to the current embodiment of the present invention includes applying a sensing voltage (operation S110) and generating compensated image data (operation S120).
Here, the organic light-emitting display includes a plurality of pixels PX, each including an organic light-emitting device EL and a second transistor T2 (i.e., a driving transistor) having a first electrode connected to the organic light-emitting device EL. The organic light-emitting display may be the organic light-emitting display 10 of FIGS. 1 through 7, and thus a detailed description thereof will be omitted. In addition, FIGS. 1 through 7 will be referred to for the description of the current embodiment.
First, a sensing voltage is applied (operation S110).
The duration of applying of the sensing voltage (operation S110) may include a first period t1 and a second period t2. The first period t1 may be a period of time during which the second transistor T2 (i.e., the driving transistor) is completely shut off, and the second period t2 may be a period of time during which a voltage difference is created between both terminals of the organic light-emitting device EL by applying a sensing voltage Vs to a third node N3. The first period t1 may be a period of time during which a first transistor T1 is turned on, and the second period t2 may be a period of time during which a third transistor T3 is turned on. In other words, the first transistor T1 and the third transistor T3 may be turned on sequentially.
In the first period t1, the second transistor T2 (i.e., the driving transistor) may be completely turned off. Specifically, in the first period t1, the same or substantially the same voltage may be applied to a gate electrode and the first electrode of the second transistor T2. The sensing voltage Vs of a specific level may be supplied to the gate electrode of the second transistor T2. In other words, in the first period t1, the first transistor T1 may be turned on by a scan signal and deliver the sensing voltage Vs received through a data line DLj to the gate electrode of the second transistor T2. The gate electrode of the second transistor T2 may be charged with the sensing voltage Vs. The sensing voltage Vs may be a voltage that turns off the second transistor T2. In other words, the second transistor T2 (i.e., the driving transistor) may be turned off by the sensing voltage Vs. Here, a voltage of the same or substantially the same level as that of the sensing voltage Vs may be provided to a second node N2 to which a first electrode of the first transistor T1 is connected. In other words, the level of a first power supply voltage ELVDD connected to the second node N2 may be set to the level of the sensing voltage Vs. The first power supply voltage ELVDD may be at a high level H until a sensing mode is activated. In other words, the first power supply voltage ELVDD may maintain the high level H such that a voltage difference is created between the terminals of the second transistor T2 (i.e., the driving transistor). However, when the sensing mode is activated, the level of the first power supply voltage ELVDD may be set to the level of the sensing voltage Vs. Since the sensing voltage Vs is supplied to the third node N3 in the second period t2, it may be applied to both the first and second electrodes of the second transistor T2 (i.e., the driving transistor). In other words, a voltage difference between the first and second electrodes of the second transistor T2 may be 0 V. Accordingly, the generation of an electric current by the second transistor T2 may be completely or substantially prevented.
In the second period t2, the sensing voltage Vs may be applied to the third node N3. In the second period t2, the third transistor T3 may be turned on by a sensing control signal, and the sensing voltage Vs supplied through the data line DLj may be provided to the third node N3 through the third transistor T3. The third node N3 may be charged with the sensing voltage Vs, and a voltage difference between the first and second electrodes of the second transistor T2 (i.e., the driving transistor) may be substantially 0 V. Thus, the second transistor T2 may be completely turned off. Since a first electrode of the organic light-emitting device EL is connected to the third node N3 and a second electrode of the organic light-emitting device EL is connected to a second power supply voltage ELVSS, a specific voltage difference may be created between both terminals of the organic light-emitting device EL. Accordingly, an electric current corresponding to this voltage difference may flow through the organic light-emitting device EL, causing the organic light-emitting device EL to emit light at a specific luminance level.
Next, compensated image data is generated (operation S120).
A sensor 160 may read out degradation information based on the sensing voltage Vs. In other words, sensing data SD may be detected using various suitable known methods. For example, the sensing data SD may be read out by measuring the luminance of the organic light-emitting device EL. However, the present invention is not limited thereto, and the sensing data SD may also be read out by measuring a current or voltage flowing through the organic light-emitting device EL. The sensor 160 may convert the read-out sensing data SD into a digital value. The digital value generated by each pixel PX may be mapped to a memory unit (or memory) and provided to a controller 120 as the sensing data SD. The controller 120 may generate compensated image data DATA1 by compensating image data DATA using the received sensing data SD. Specifically, an image compensator 123 may generate the compensated image data DATA1 by correcting the image data DATA such that a voltage increased by an amount corresponding to a luminance reduction caused by the degradation of the organic light-emitting device EL may be applied to a degraded pixel.
The method of driving the organic light-emitting display according to the current embodiment may prevent or reduce the generation of a leakage current by completely shutting off the second transistor T2 (i.e., the driving transistor). Accordingly, the degradation information of the organic light-emitting device EL may be read out more accurately based on the sensing voltage Vs, making more accurate data compensation possible.
Other components used in the method of driving the organic light-emitting display according to the current embodiment are substantially identical to those of the organic light-emitting display 10 of FIGS. 1 through 7 identified by the same names, and thus a detailed description thereof is omitted.
In some embodiments, in the applying of the sensing voltage included in the method of driving the organic light-emitting display, the first transistor T1 and the third transistor T3 may be turned on concurrently (e.g., simultaneously). In other words, a scan signal and a sensing control signal may be provided at the same or substantially the same time. Voltage levels of the gate electrode, the first electrode and the second electrode of the second transistor T2 (i.e., a driving transistor) may all be set to the level of the sensing voltage Vs. In the method of driving the organic light-emitting display according to the current embodiment, the driving transistor may be turned off by concurrently (e.g., simultaneously applying the same or substantially the same voltage to the gate electrode, the first electrode and the second electrode of the driving transistor. Therefore, the time required to apply the sensing voltage Vs may be reduced.
Embodiments of the present invention provide at least one of the following aspects.
It is possible to measure more accurate degradation information.
Accordingly, since more accurate degradation compensation may be performed, display quality may be improved.
However, the effects of the present invention are not restricted to the one set forth herein. The above and other effects of embodiments of the present invention will become more apparent to one of ordinary skill in the art to which the present invention pertains by referencing the claims.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. The exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation.

Claims (20)

What is claimed is:
1. An organic light-emitting display comprising:
a first transistor comprising:
a gate electrode connected to a scan line;
a first electrode connected to a data line; and
a second electrode connected to a first node;
a second transistor comprising:
a gate electrode connected to the first node;
a first electrode connected to a first power supply voltage; and
a second electrode connected to a third node;
a third transistor comprising:
a gate electrode connected to a sensing control line;
a first electrode connected to the data line; and
a second electrode connected to the third node; and
an organic light-emitting device comprising:
an anode connected to the third node; and
a cathode connected to a second power supply voltage,
wherein the first power supply voltage is set to a level of a sensing voltage for a period of time during which the sensing voltage is provided to the data line.
2. The organic light-emitting display of claim 1, wherein a same voltage is applied to the gate electrode, the first electrode, and the second electrode of the second transistor.
3. The organic light-emitting display of claim 1, wherein the first transistor and the third transistor are configured to be turned on sequentially.
4. The organic light-emitting display of claim 1, wherein the first transistor and the third transistor are configured to be turned on concurrently.
5. The organic light-emitting display of claim 1, further comprising:
a sensor configured to read out sensing data of the organic light-emitting device corresponding to the sensing voltage.
6. The organic light-emitting display of claim 5, further comprising:
a controller configured to receive the sensing data from the sensor and to generate compensated image data by compensating an image signal received from an external source using the sensing data.
7. The organic light-emitting display of claim 6, further comprising:
a power supply configured to output the first power supply voltage and the second power supply voltage.
8. The organic light-emitting display of claim 7,
wherein the controller is configured to output driving signals for controlling the sensor and the power supply, and
wherein the power supply comprises:
a switching device connected to a high-level supply terminal or a sensing-level supply terminal according to the driving signals received from the controller.
9. An organic light-emitting display comprising:
a plurality of pixels, each pixel comprising:
an organic light-emitting device; and
a driving transistor comprising:
a first electrode connected to the organic light-emitting device; and
a second electrode;
a sensor configured to read out degradation information of the organic light-emitting device by applying a sensing voltage of a specific level to a gate electrode and the first electrode of the driving transistor; and
a power supply configured to supply a power supply voltage of a same level as that of the sensing voltage to the second electrode of the driving transistor.
10. The organic light-emitting display of claim 9, wherein each of the pixels further comprises:
a control transistor configured to supply the sensing voltage to the gate electrode of the driving transistor; and
a sensing transistor configured to supply the sensing voltage to the first electrode of the driving transistor.
11. The organic light-emitting display of claim 10, wherein the control transistor and the sensing transistor are configured to be turned on sequentially.
12. The organic light-emitting display of claim 10, wherein the control transistor and the sensing transistor are configured to be turned on concurrently.
13. The organic light-emitting display of claim 9, wherein the sensor is configured to read out sensing data of the organic light-emitting device corresponding to the sensing voltage.
14. The organic light-emitting display of claim 13, further comprising:
a controller configured to receive the sensing data from the sensor and to generate compensated image data by compensating an image signal received from an external source using the sensing data.
15. The organic light-emitting display of claim 14,
wherein the controller is configured to output driving signals for controlling the sensor and the power supply, and
wherein the power supply comprises:
a switching device connected to a high-level supply terminal or a sensing-level supply terminal according to the driving signals received from the controller.
16. A method of driving an organic light-emitting display comprising:
a plurality of pixels, each pixel comprising:
an organic light-emitting device; and
a driving transistor comprising:
a first electrode connected to the organic light-emitting device; and
a second electrode,
the method comprising:
reading out degradation information of the organic light-emitting device by applying a sensing voltage of a specific level to a gate electrode and the first electrode of the driving transistor; and
generating compensated image data by compensating an image signal received from an external source using the degradation information,
wherein a power supply voltage of a same level as that of the sensing voltage is supplied to the second electrode of the driving transistor in the reading out of the degradation information.
17. The method of claim 16, wherein each of the pixels further comprises:
a control transistor which supplies the sensing voltage to the gate electrode of the driving transistor; and
a sensing transistor which supplies the sensing voltage to the first electrode of the driving transistor.
18. The method of claim 17, wherein the control transistor and the sensing transistor are turned on sequentially.
19. The method of claim 17, wherein the control transistor and the sensing transistor are turned on concurrently.
20. The method of claim 16, wherein compensated image data is generated by compensating an image signal received from an external source using sensing data corresponding to the degradation information of the organic light-emitting device.
US14/656,570 2014-11-19 2015-03-12 Organic light emitting display having a variable power supply for organic light emitting diode sensing and method of driving the same Active 2035-12-29 US9697774B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR10-2014-0161646 2014-11-19
KR1020140161646A KR102278599B1 (en) 2014-11-19 2014-11-19 Orgainic light emitting display and driving method for the same

Publications (2)

Publication Number Publication Date
US20160140902A1 US20160140902A1 (en) 2016-05-19
US9697774B2 true US9697774B2 (en) 2017-07-04

Family

ID=55962229

Family Applications (1)

Application Number Title Priority Date Filing Date
US14/656,570 Active 2035-12-29 US9697774B2 (en) 2014-11-19 2015-03-12 Organic light emitting display having a variable power supply for organic light emitting diode sensing and method of driving the same

Country Status (2)

Country Link
US (1) US9697774B2 (en)
KR (1) KR102278599B1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102267600B1 (en) * 2014-11-19 2021-06-23 엘지디스플레이 주식회사 Organic light emitting diode display
US10043050B2 (en) * 2016-03-07 2018-08-07 Microsoft Technology Licensing, Llc Image sensing with a display
DE102018220075A1 (en) * 2017-11-22 2019-05-23 Ignis Innovation Inc. DISPLAY, PIXEL CIRCUIT AND METHOD
US11749143B2 (en) * 2017-11-22 2023-09-05 Ignis Innovation Inc. Pixel circuit, display, and method
CN113192451B (en) * 2021-04-28 2024-04-19 京东方科技集团股份有限公司 Compensation control method and display device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060158402A1 (en) * 2004-12-15 2006-07-20 Arokia Nathan Method and system for programming, calibrating and driving a light emitting device display
US20110007067A1 (en) * 2009-07-10 2011-01-13 Do-Hyung Ryu Organic light emitting display and driving method thereof
KR20130024744A (en) 2011-08-30 2013-03-08 엘지디스플레이 주식회사 Organic light emitting diode display device for sensing pixel current and method for sensing pixel current thereof
KR20130038872A (en) 2011-09-14 2013-04-18 보에 테크놀로지 그룹 컴퍼니 리미티드 Pixel structure of organic light emitting diode and driving method thereof
KR20130104564A (en) 2012-03-14 2013-09-25 삼성디스플레이 주식회사 Method for detecting array and array detecting apparatus
KR20130107909A (en) 2012-03-23 2013-10-02 엘지디스플레이 주식회사 Organic light emitting diode display device and method of measuring pixel current of the same
US20150348504A1 (en) * 2014-06-03 2015-12-03 LuxVue Technology Corporation Interactive display panel with emitting and sensing diodes

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100673759B1 (en) * 2004-08-30 2007-01-24 삼성에스디아이 주식회사 Light emitting display
JP4874679B2 (en) 2006-03-10 2012-02-15 東芝モバイルディスプレイ株式会社 EL display device
KR100833760B1 (en) 2007-01-16 2008-05-29 삼성에스디아이 주식회사 Organic light emitting display
KR102033756B1 (en) * 2013-03-18 2019-10-17 엘지디스플레이 주식회사 Organic Light Emitting Display Device and Driving Method thereof

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060158402A1 (en) * 2004-12-15 2006-07-20 Arokia Nathan Method and system for programming, calibrating and driving a light emitting device display
US20110007067A1 (en) * 2009-07-10 2011-01-13 Do-Hyung Ryu Organic light emitting display and driving method thereof
KR20130024744A (en) 2011-08-30 2013-03-08 엘지디스플레이 주식회사 Organic light emitting diode display device for sensing pixel current and method for sensing pixel current thereof
KR20130038872A (en) 2011-09-14 2013-04-18 보에 테크놀로지 그룹 컴퍼니 리미티드 Pixel structure of organic light emitting diode and driving method thereof
US20130293450A1 (en) * 2011-09-14 2013-11-07 Boe Technology Group Co., Ltd. Pixel structure of organic light emitting diode and driving method thereof
KR20130104564A (en) 2012-03-14 2013-09-25 삼성디스플레이 주식회사 Method for detecting array and array detecting apparatus
KR20130107909A (en) 2012-03-23 2013-10-02 엘지디스플레이 주식회사 Organic light emitting diode display device and method of measuring pixel current of the same
US20150348504A1 (en) * 2014-06-03 2015-12-03 LuxVue Technology Corporation Interactive display panel with emitting and sensing diodes

Also Published As

Publication number Publication date
US20160140902A1 (en) 2016-05-19
KR20160060217A (en) 2016-05-30
KR102278599B1 (en) 2021-07-16

Similar Documents

Publication Publication Date Title
US10204565B2 (en) Organic light emitting display panel having a sensing transistor and method of driving thereof
US9812067B2 (en) Organic light-emitting display device and driving method thereof
US10665173B2 (en) Organic light emitting display device capable of compensating for deviation and deterioration in pixel
US9679516B2 (en) Organic light emitting display and method for driving the same
US9812062B2 (en) Display apparatus and method of driving the same
KR101760090B1 (en) Pixel and Organic Light Emitting Display Device Using the same
US20190012948A1 (en) Pixel circuit, and display device and driving method therefor
US8570249B2 (en) Pixel coupled to three horizontal lines and organic light emitting display device using the same
US9601051B2 (en) Organic light-emitting display and method of compensating for degradation of the same
KR102028504B1 (en) Organic light-emtting diode display device incuding compensation circuit
US9747841B2 (en) Electro-optical device and driving method thereof
KR101481676B1 (en) Light emitting display device
KR20160007900A (en) Pixel, pixel driving method, and display device comprising the pixel
US9697774B2 (en) Organic light emitting display having a variable power supply for organic light emitting diode sensing and method of driving the same
KR20110124656A (en) Organic light emitting display and driving method thereof
KR20140134046A (en) Organic Light Emitting Display Device and Driving Method Threrof
US10600347B2 (en) Organic light emitting display device and controller
KR20160030597A (en) Organic Light Emitting Display Device
KR20210069234A (en) Organic light emitting display apparatus and driving method thereof
KR101901757B1 (en) Organic light emitting diode display device and method of driving the same
KR102409494B1 (en) Organic light emitting display apparatus and the driving method thereof
US10366652B2 (en) Organic light-emitting display apparatus
KR20160055324A (en) Organic light emitting display device and organic light emitting display panel
KR102319202B1 (en) Organic light emitting display device
KR20170118436A (en) Display device

Legal Events

Date Code Title Description
AS Assignment

Owner name: SAMSUNG DISPLAY CO., LTD., KOREA, REPUBLIC OF

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:YANG, JIN WOOK;REEL/FRAME:035208/0568

Effective date: 20150303

STCF Information on status: patent grant

Free format text: PATENTED CASE

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 4